The mountains, forests and river networks of Laos are home to a range of animals both endemic to the country and shared with its Southeast Asian neighbours. Nearly half of the animal species natives to Thailand are shared by Laos, with the higher forest cover and fewer hunters meaning that numbers are often greater in Laos. Almost all wild animals however are threatened to some extent by hunting and habitat loss; see Environmental Issues.

In spite of this Laos has seen several new species discovered in recent years, while others thought to be extinct have turned up in remote forests. Given their rarity, these newly discovered species are on the endangered list.

As in Cambodia, Vietnam, Myanmar and much of Thailand, most of the fauna in Laos belong to the Indochinese zoogeographic realm (as opposed to the Sundaic domain found south of the Isthmus of Kra in southern Thailand or the Palaearctic to the north in China).

Notable mammals endemic to Laos include the lesser panda, raccoon dog, Lao marmoset rat, Owston's civet and the pygmy slow loris. Other impor­tant exotic species found elsewhere in the region include the Malayan and Chinese pangolins, 10 species of civet, marbled cat, Javan and crab-eating mongoose, the serow (sometimes called Asian mountain goat) and goral (another type of goat-antelope), and cat species including the leopard cat and Asian golden cat.

Among the most notable of Laos's wildlife are the primates. Several smaller species are known, including the Phayre's leaf monkey, Francois' langur, Douc langur and several macaques. Two other primates that are endemic to Laos are the concolour gibbon and snub-nosed langur. But it's the five species of gibbon that attract most attention. Sadly, the black-cheeked crested gibbon is endangered, being hunted both for its meat and to be sold as pet in Thailand. Several projects, including one treetop affair that would rather keep a low profile, are working to educate local communities to set aside safe areas for the gibbons.